Find & Manage Your Patient Assistance Programs
Estimated patient savings $600,000,000.00

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.


(mag-NEE-zee-um hi-DROX-ide)

COMMON BRAND NAME(S): Phillips' Milk of Magnesia


This medication is used to treat occasional episodes of constipation. It acts to produce a bowel movement within 6 hours of taking a dose. This medication is also used for upset stomach caused by heartburn, acid indigestion or sour stomach; for peptic ulcer, hiatal hernia or other conditions caused by excess stomach acid; and to prevent ulcers or bleeding from ulcers.

How To Use

Take this medication as prescribed. Use only temporarily to relieve constipation. When regularity returns, stop using the medication. Prolonged or continued use may result in laxative dependence. To be effective, chewable tablets must be chewed thoroughly before swallowing followed by a full glass of water. Shake liquid forms well before pouring each dose. Do not take any other medication within 1 to 2 hours of taking this medication. Since magnesium hydroxide coats the stomach, it can prevent other drugs from being absorbed properly if taken at the same time.

Side Effects

This medication may cause diarrhea. If diarrhea persists or worsens, inform your doctor. Notify your doctor if the following effects occur: black/tarry stools or rectal bleeding. If you notice other effects not listed above, contact your doctor or pharmacist.


Do not take magnesium hydroxide before consulting your doctor if you have the following conditions: kidney disease, stomach/abdominal pain, nausea or vomiting. Do not give this medication to a child under six years of age without first consulting a doctor. Tell your doctor if you are pregnant before using this medication. It is not known if magnesium hydroxide is excreted into breast milk. Though there have been no reports (to date) of harm to nursing infants, consult your doctor before using this medicine.

Drug Interactions

Tell your doctor of all prescription and nonprescription drugs you may use, especially of: antibiotics, quinidine, sodium polystyrene sulfonate. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately.


Refrigerating the liquid may improve the taste. (Do not freeze). The liquid form works faster and is more effective than the other forms. However, chewable tablets may be more convenient.

Missed Dose

If you miss a dose, take it as soon as remembered; do not take if it is almost time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.


Store capsule and tablet forms at room temperature away from moisture and sunlight. Do not store in the bathroom. Do not freeze liquid forms of this medication.